Geller, Robert Dennis, Giclas, Patricia C · BMJ case reports · 2009 · DOI
This report follows one patient who developed ME/CFS after a severe Epstein-Barr virus infection. Standard medical tests came back normal, but when doctors tested for complement activation (part of the immune system's inflammatory response), they found it was abnormally active. The patient remained unwell for about 2 years while showing these signs of complement activation, then recovered.
This study introduces complement activation as a potentially measurable biomarker in ME/CFS, offering a testable immune mechanism in patients with post-viral onset. It supports the biological basis of ME/CFS at a time when many conventional tests appear normal, validating the experience of patients with negative standard workups.
This case report does not prove that complement activation causes ME/CFS, only that it was present in one patient. It does not establish how common this finding is across ME/CFS populations, whether complement activation is specific to post-viral cases, or what role it plays in disease pathogenesis versus being a secondary phenomenon.
About the PEM badge: “PEM required” means post-exertional malaise was an explicit required diagnostic criterion for participant inclusion in this study — not that PEM was studied, observed, or discussed. Studies using criteria that do not require PEM (e.g. Fukuda, Oxford) are tagged “PEM not required”. How the atlas works →
The first block is for the primary paper and is the citation you should use in research work. The atlas-snapshot line only applies if you are specifically referring to this atlas’s reading of the paper on the date shown.
Primary citation
Geller, Robert Dennis & Giclas, Patricia C (2009). Chronic fatigue syndrome and complement activation.. BMJ case reports. https://doi.org/10.1136/bcr.08.2008.0819
BibTeX
@article{mecfsatlas-geller-2009-chronic-fatigue,
author = {Geller, Robert Dennis and Giclas, Patricia C},
title = {Chronic fatigue syndrome and complement activation.},
journal = {BMJ case reports},
year = {2009},
doi = {10.1136/bcr.08.2008.0819},
note = {PubMed: 21686614},
url = {https://www.mecfsatlas.com/evidence/geller-2009-chronic-fatigue},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-30. https://www.mecfsatlas.com/evidence/geller-2009-chronic-fatigue
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